Phoenix
by MegaBadBunny
Summary: Donna's synapses rearrange, her neural pathways split and re-form, the capacity of her memory centers expand and grow until she thinks the pressure might rupture her skull. Through it all, she waits, because even amidst the overwhelming fear and pain, she knows that something wonderful is about to happen. Oh, something brilliant!
1. Part 1

Donna can physically feel the passage of time, feel it thicken and slow, as her mind begins to die.

Lying on her back in a Dalek warship, she waits, patient, while her brain explodes in a fiery blaze. Her synapses rearrange, her neural pathways split and re-form, the capacity of her memory centers expand and grow until she thinks the pressure might rupture her skull. Through it all, she waits, because even amidst the overwhelming fear and pain, she knows that something wonderful is about to happen.

Oh, something _brilliant_.

She feels her eyes and her brain burn, glow, and rebirth, and thinks this is what a phoenix must feel like. Suddenly she's closing all Z-neutrino relay loops as easy as pie while thousands of Daleks scream and rage about her. She figures out how to initiate a bio-electric dampening field and is delighted to note that it's as easy as adding columns in a spreadsheet. Matrices, psychokinesis, magnetrons—it's laughable how easy all of this stuff is, and she grins as all of these phrases come pouring out of her mouth like some kind of turbo-charged space word vomit.

No wonder the Doctor talks all the time. How can he ever stop?

The new Doctor, the Donna-Doctor, tells her she's brilliant, and she doesn't disagree, as more and more knowledge and memories fill up her brain, each of them vying for attention, screaming for her to know the exact atomic weight of each of the stars in the Kasterborous constellation, the color of a supernova epicenter in Ursa Minor, the chemical composition of the dyes lightening and darkening Jackie and Sarah Jane's hair, respectively. The floodgates have opened and in pour memories of singing forests and ice warriors and Aztec princesses and the exact feel and taste of a kiss to Rose Tyler with the power of the Vortex surging through her veins, like a fine champagne that bursts behind her eyelids in tiny fireworks of gold and sweet. Donna drinks in the memories and knowledge like a starving plant in the desert, and she and her Doctors send all the planets home, one-by-one, laughing and grinning all the while, as a happy sort of chaos descends around them.

And she, Donna, the temp, the hopeless, the unspecial, saves the day.

* * *

><p>She watches as the Time Lord Doctor proper deserts Rose on a beach a universe away with his fresh new self, and she wonders. She's not surprised—how can she be, with his knowledge in her brain, his memories? She knows him as well as (no, better than) the back of her own hand now. There's no way he sent Rose away out of some misplaced fear for Donna's feelings, because firstly, he doesn't think like that, and secondly, he ought to know Donna well enough to realize that she would be fine with Rose around. She's not the jealous type.<p>

(Well. She amends. Donna's certainly the jealous type. But she's not the type to be intimidated. Not by other women, and certainly not by men, and definitely not by all of the Time Lord mental detritus crowding about in her skull, pressing at the seams like it will leak out any moment.)

What bothers her are the unseen possibilities, the other outcomes that the Doctor never takes a moment to consider. For all of his brilliance, and all of his madcap genius, he certainly seems a bit stuck in his ways, and more often than not, his expansive verbal lexicon seems awfully focused on one small and stupid word: _impossible_.

Donna wonders why Rose couldn't stay.

She has calculated approximately thirty-nine scenarios in which Rose and the half-human-Donna-Doctor could happily remain, with her and the Doctor proper, in this universe. She imagines a TARDIS with four occupants instead of two, with the Doctor finally relaxed and happy in a way she never imagined she would see him. Rose and the Doctor proper could snuggle up and be ridiculously and disgustingly adorable together, and Donna and the Donna-Doctor could pretend not to notice while they tinker with the time rotor (which Donna is now convinced she can rig up to brew a decent cup of coffee while they're traveling from one adventure to the next; all she needs is a hyper-carburetor, and she knows for a fact that you can find those in 67th-century New New Zealand).

A lifetime plays out in Donna's head, an entire timeline wherein she lives out the remainder of her human life (approximately 15,330 days, 13 hours, and 7 minutes if she can resolve this nagging mental overload problem and reduce her sodium intake, she calculates—ooh, unless she visits Gaviscinia's third moon, then she might be able to talk them into giving her some of that life-prolonging carbon-6 concoction, extending her life by at least another decade, assuming she can figure out how to nullify that nasty third eyeball side effect): she sees the four of them having adventures on Proteus Kek, watches them journey to the emerald fields of Fhennor, thinks of a four-person quest for the Bryyghian version of the Holy Grail. She imagines a trip to the court of Henry VIII, and Rose gives the king a sound scolding; Donna and the Doctors just laugh and laugh, and back on the TARDIS, the Doctor proper pulls Rose in for a kiss, and Donna and her Doctor just roll their eyes. The Doctor proper and the Donna-Doctor have their spats and argue brilliantly and pettily and hilariously and Rose and Donna love them both in different but equal ways, and yes, sometimes the Donna-Doctor is jealous, and sometimes it eats him up inside and Donna can feel his hurt from across the room, but one day Donna nudges him toward a temple on the ancient planet of Meridian and he meets the brilliant young archaeologist River Song and sometimes the TARDIS has five people in it instead of four, and there's always another adventure anyway. Donna doesn't imagine any children, no pitter-patter of bare little feet against the console grating, but she catches an ever-so-brief glimpse of a red-headed girl and something that looks like the end of the universe wrapped up in one big bang, and the entirety of the Doctor's and the Donna-Doctor's and the Doctor-Donna's existence hinging on the memory of a nursery rhyme—

Her head starts to hurt, cracks forming in the eggshell membrane surrounding her grey matter. Something is trying to hatch out, trying to claw its way past the fragile white walls.

Donna closes her eyes against the rush of potential timelines and maybe-happenings and can't tell if she's seeing the future or just the possibility of it. She sees star whales and vampires that aren't really vampires and a man who thinks himself the Doctor but isn't, she sees the return of someone who calls himself 'the Master' and even though she has no idea who that is, the memory is buried too deep to access just yet, the very thought of those words sends a bolt of fearborne nausea straight to her core. She knows pi to its eight-hundredth digit and those numbers are crowding in with everything else, clamoring to be heard over Rose laughing with the two Doctors, and Donna and Rose getting a much-needed girls' day away at the Palatial Spa of Space Florentine and one last trip to Jackie's bedside and a revolution on Xanthus Blue and suddenly Donna is recalling the life cycle of the Xanthian bat-birds, hatch and die and rebirth, a cycle lasting 3 Xanthian years, each of which is the length of exactly two and a half Earth years, a fact disputed by some of Gallifrey's more prestigious scholars, and gods, gods, _Gallifrey_, Donna reaches up to find her nose is bleeding, but _Gallifrey_, just the thought of the word makes Donna's skull split even further, and she sees slopes and slopes of red grass and silver forests and clear rivers and moons and suns and clouds and turrets and domes and Donna knows the chemical composition of each, knows each of the 751 elements on the planet of Gallifrey, knows their uses, sees the Doctor preparing a chemical makeup for the preservation of the dead, enacting funeral rites for a body under a blanket, the last of three, and the emptiness ravages his being like some kind of cancer or hideous black hole, and with all of his capacity for love and knowledge and wonder, he has just as much capacity for fear and loneliness and hate—

Donna lets out a gasp, a choke, a dry heave. Her nose is still bleeding and her lungs are seizing up. It feels like all of the air has left the room, though Donna knows such a thing would be impossible; it would take seventeen hundred thirty-six point seven hours for the TARDIS to lose all of its air, and she would be dead seventeen hundred thirty-four point two hours in.

(Dead like the body under the blanket, like the two bodies preceding it, all neatly-wrapped and preserved, their faces arranged carefully, expressionless and pale, porcelain Victorian dolls with their glass doll-eyes gently closed in a facsimile of sleep. Donna curses her eighth incarnation and his uncanny ability for prescience; she wonders why anyone would choose to see such horrible things, and she winches her eyes shut against the tears that should be falling.)

The bodies of the future-ghosts weigh heavy in her arms, but Donna does not weep. She understands.

It would be far easier, she realizes, for the Doctor to outlive one person instead of three.

It would be easier still if he didn't have to outlive anyone at all.


	2. Part 2

Maybe the Doctor just doesn't want anyone to know what she knows.

That's what Donna thinks when he advances on her, hands outstretched. It's a motion meant to heal, but Donna recoils.

She doesn't want to forget.

Donna pleads. She cries. She doesn't mean to cry but the tears burn and push out of her eyes, salty and bitter and thick as blood, the neurochemicals in her brain firing and misfiring in response to emotional stimuli and hormonal imbalances and Donna knows she can't stop it, it's all her treacherous body running on automatic, but she tells herself that if she seems strong, then maybe he'll stop.

(He won't, and she knows it.)

She thinks that the pity in his eyes is worse than anything else, the pity and the concern and the disgusting sadness. It's so human. They're both so human, both of them, and she thinks at least she can't help it, but he can, he can be better than this. He can shut those human feelings down and let Donna live like this for however long she's got, because living with this freedom, this knowledge, this sense of power and importance and connection with the universe is worth trimming down the remainder of her 15,330 days, 13 hours, and 4 minutes. It's not his decision to make, how long the rest of her life should be.

What was the point of all of this if she doesn't remember?

She tells him "forever," and thinks maybe it tears him up under that sad stare; she has a distant memory of another woman telling him the same thing on a windswept moon, and him taking her hand in his, and him believing her. And she realizes how short "forever" can be.

Donna knows that she is dying, can feel her brain withering as her synapses burn out. She knows that in order to survive, the Doctor will have to hollow her out. But how can she go back to living the way she was, with everything she's seen, done, become? Will she really forget it all? Is the Doctor really so cruel? Can she really live like that?

She can't, she realizes, as darkness clouds the edges of her vision and his cool fingers press against her temples. She watches the memories and knowledge, a lifetime of his and over a year's worth of hers, fly by her eyes like an unraveling film, images of Pompeii and Daleks and snow and fire. He only thinks he is saving her, but really, she'll be dead all the same. He's murdering the person she has become, even if he's doing it in the kindest way possible.

He has been sorry for so many people, and now he's sorry for her.

_The nicest killer you'll ever meet_, she thinks before consciousness slips out of her grasp.

* * *

><p>Donna wakes up with one hell of a headache, still has her clothes on and everything, and she thinks that will be the last time she binges on peppermint schnapps. Really, who let her drink that much? She bets it was Neris. Probably let her get sloshed so she'd make a fool of herself all over the place. Oohh, she's going to have some words with that little tramp, she really is.<p>

And what's this about the earth moving? The earth? Moving? The whole world's gone bonkers, it has. Has everyone but her lost their marbles?

She natters on the phone for a bit and tries to ignore that strange, watery look that Gramps is shooting her way. Maybe Gramps got into the schnapps too.

There's a skinny pinstriped bloke hanging about the place as well, but Donna doesn't recognize him. He looks miserable as hell, though. Poor sap. Donna manages to feel sorry for him for approximately .009 seconds before the convo on the other side of the phone shifts dramatically in tone and suddenly she finds herself gossiping about Veena's dating habits. Planets in the sky, the earth moving, cute bartenders and two for one lagers, Donna's not stupid.

The sad skinny bloke says goodbye to her before he goes, almost like he knows her or something.

Something about him makes the hairs on the back of her neck stand on edge. And just for an instant, she has a flash of him cradling her in his arms, rocking her gently, whispering how sorry he is over and over and over again, and she can feel down to her bones how very, very much he hates himself.

She shudders. What a weirdo.


End file.
